Just passed my Cloud+, kind of a nice pick me up after failing my last two cert exams (CCENT, CASP), but it was a good challenge. I brushed up on:
Hypervisors: types, pros & cons of each
Data Tiers: the downtime of each, and the layout/structure of them each - never really appeared on the exam though
and that was about it, I got a 778/900, so I didn't pass by much, but I didn't really review any of my answers, I felt my gut was good enough for this one

I'd definitely say that some content from my A+, Net+, Sec+, and CCENT studies were all in this exam in bits and pieces